remove the cap on pillow
remove the cap on pillow

Remove the cap on Pillow and require the latest sphinxmark to ensure
that we have compatible versions of the libraries.

Change-Id: Ib053e48f72020bef64987bc22ded4d83ea322be4
Signed-off-by: Doug Hellmann <0798ebecfb7bc4dfb9d0445c2fa030eb64e1fa1c@doughellmann.com>

openstack/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals